Microsoft is bringing back the Start button in Windows 8.1, but it may be preparing to kill a different kind of button in the next major update for its smartphone operating system, scheduled for release early next year.

According to a new article by Paul Thurrott, a source has revealed Microsoft plans to get rid of the physical back button in Windows Phone 8.1, as users "don't realize what they're doing" when using the button multiple times. The button is also responsible for opening the multitasking screen in Windows Phone, with users holding the button down to see a series of tiles showing recent apps. Thurrott's source didn't say how the screen would be opened with the back button gone.

Currently, Microsoft uses a "back stack" navigation system in Windows Phone, with a press of the back button returning users to either the previous "page" in an app or closing the app if a user is on its first screen. If a contextual menu is open, pressing the back button will close the menu.

In addition to the removal of the back button, Thurrott said his source revealed Microsoft will add support for devices with up to 10-inch screens. Microsoft will soon support devices with up to 6-inch screens when it releases the GDR3 update, which is expected to be released around the time of Nokia's 6-inch Lumia 1520. That smartphone and others will likely be revealed at Nokia's Oct. 22 press event. The decision could have implications for the company's flagship Windows operating system, as Windows 8.1 and Windows RT 8.1 will support tablets as small as about 7 inches.

Whether Microsoft merges Windows Phone with Windows remains to be seen, but the company has strongly hinted at the possibility, saying it will create a unified app platform for all its operating systems.

Other improvements scheduled for Windows Phone 8.1, according to Thurrott, include multitasking improvements for notifications and background processes. A notification center has long been rumored for the update, with alleged screenshots of the function being leaked in recent months.

Thurrott says to take the source's claims "with a grain of salt" but adds that the information appears credible.